Various pneumatic tires have been proposed which contain a built-in sealant layer based upon a depolymerized butyl rubber layer.
For example, in U.S. Pat. No. 4,895,610 it is proposed to build a layer of butyl rubber-based composition into a tire which contains a polyisobutylene polymer and an organoperoxide, following which under a conditions of elevated temperature used to cure the tire, a major portion of the butyl rubber is presented as being depolymerized to form a tacky material which has puncture sealant properties.
U.S. Pat. Nos. 4,228,839, 4,171,237 and 4,140,167 also relate to a sealant layer in a tire formed by depolymerizing and crosslinking a butyl rubber based rubber composition, particularly by irradiation treatment.
U.S. patent application Ser. No. 10/171,057, filed Jun. 13, 2002, relates to a tire with built-in sealant comprised of a partially depolymerized butyl rubber via an organoperoxide which contains a particulate pre-cured rubber dispersed in said butyl rubber.
U.S. patent application Ser. No. 10/368,259, filed Feb. 17, 2003, relates to a tire with built-in sealant comprised of a partially depolymerized butyl rubber via an organoperoxide which contains a particulate filler comprised of carbon black and/or coal dust and optionally, a liquid diene based polymer, short fibers, hollow glass microspheres and rubber processing oil wherein said liquid polymer is not optional where said particulate filler is exclusively rubber reinforcing carbon black.
Historically, other patent publications relate to tire constructions, sealant compositions and methods wherein a sealant material is positioned between calendered rubber layers. For example, see U.S. Pat. No. 3,048,509 and said U.S. Pat. No. 4,228,839.
In the description of this invention, the term “agricultural seed flour” refers to seeds, including their embryo, or nucleus, and which may also include their accompanying seed shell and husk, obtained from cultivated, agricultural plants as hereinbefore discussed. Typically such grains, with or without their shell and/or husks, are ground into small particles and then usually sifted to through a fine mesh screen to obtain a relatively consistent average particle size which may sometimes be referred to as “flour”.
The term “phr” is used to designate parts by weight of an ingredient per 100 parts of elastomer unless otherwise indicated. The terms “elastomer” and “rubber” are used interchangeably unless otherwise indicated. The terms “cure” and “vulcanize” are used interchangeably unless otherwise indicated.